Silver halide meulsions containing cationic oxonol and benzylidene dyes



United States Patent SILVER HALIDE EMULSIONS CONTAINING CATI- ONIC OXONOL AND BENZYLIDENE DYES Donald W. Heseltine and Lewis L. Lincoln, Rochester,

N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., 'a corporation of New Jersey Filed Mar. 10, 1960, Ser. No. 14,139 8 Claims. (Cl. 9684) This invention relates to a novel class of dyes, and more particularly to cationic oxonol and benzylidene dyes useful as bleachable antihalation and filter dyes, and as optical sensitizers in photographic silver halide elements.

It is known that photographic elements require, for many purposes, light screening substances incorporated therein. Such a light screening substance may be in a layer overlying a light sensitive emulsion or overlying two or more light sensitive emulsions; or it may be in a light sensitive emulsion for the purpose of modifying a light record of such an emulsion or protecting an overlying light sensitive emulsion or emulsions from the action of light of wavelength absorbed by such light screening substance; or it maybe in a layer not containing a light sensitive substance but arranged between two light sensitive emulsions; or it may be in a layer serving as a'backing on an element having one or more light sensitive emulsions (for example, to reduce halation).

In particular, light screening substances are often required 1) in overcoatings upon photographic elements to protect the light sensitive emulsion or emulsions from the action of light which his not desired to record, e.g., ultraviolet light in the case of still or moving pictures, especially color pictures, (12) in layers arranged between differentially color sensitized emulsions e.g., to protect red and green sensitized emulsions from the action of blue light and (c) in backings, forming the so-called antihalation layers, on either side of a transparent support carrying the light sensitive emulsion or emulsions.

Numerous substances have been employed as light screening materials for the purposes indicated above. Many of these, however, are not resistantto diffusion and wander from the layer in which it is intended that they should remain. Some of them are not as water soluble as is desired and therefore present problems in their incorporation in the filter layers. 3 Some dyes are not readily bleachable or destroyed in the photographicprocessing and present stain problems in the processed photographic element.

It is therefore an object of the invention to provide a novel class of dyes which are valuable for use in making light sensitive photographic elements. 1

Another object is to provide a novel class of cationic oxonol and benzylidene dyes for making light absorbing filter. layers and antihalationlayers in photographic elements which not only have valuable light absorbing characteristics but are more water soluble in neutral or in slight-1y acid solution than prior art oxonol dyes and are thus more easily incorporated in the filter layer.

Another object is to provide a novel class of dyes which are useful asphotographic sensitizers.

Another object is to provide a novel class of cationic ox-onol and benzylidene dyes for light absorbing filter layers which not only have the desired light absorbing properties and solubility properties but which are further characterized by being less subject to diffusion from the filter layer than are the prior art dyes.

Another object is to provide a novel class of dyes which not only have the above desirable characteristics but which are bleachable by the photographic developer or 3,094,418 Patented June 18, 1963 Another object is-toprovide aphotographic element having at least one sensitive silver halide emulsion layer and a light absorbing filter layer containing a dye selected from the novel class of dyes of our invention.

Still another object is to provide a photographicelement having at least one sensitive silver halide emulsion layer containing a sensitizing amount of ,a dyeselected from the novel class of dyes of our invention.

Still other objects 'will become apparent from the followingspeci-fication We have discovered that the above objects can be accomplished by the use of the, novel dyes of our invention. Our dyes have a characteristic structure which distinguishes them from the prior dyes. This structure has a methine chain witheither one or bothof its terminal carbon atomssubstituted with a pyridinium group and also,with a phenacyl group or a cyano group or a henzothiazolyl group.

The dyes of ourinvention can advantageously be represented by the following formulas:

R i R Formulas I and I I whichcan be used in practicing our alkaline solutions during the processing of the photographic element.

invention are those represented by the formulas. below. It is to be understood, however, that these illustraltive dyes are in no way to limit the dyes of our invention.

1- abenzoyl-p-dimethylaminostyryl pyridiniuni iodide y on,

1- (p-dimethylaminoplienylally lidenephenacyl py ridinium perchlorate (Dye 3) Anaclcl-l,3'dicyanopr0penylene-bis-pyridinium perchlorate Anacid-l,5dibenzoylpenta-1,3-dienyleue-bis-pyridinium perchlorate 0 QB; A} N 1- ('acyano -p diethyla1ninostyry1) pyridinium perchlorate Ana cid1,3-di (Z-benzothiazolyl) propenylene-bis-pyridinium perchlorate The dyes of our invention are produced by the reaction of a salt having -a cation with an active methylene group with any one of a number of intermediates. Among the preferred salts used to prepare the dyes of our invention are those having the cation l-phenacylpyridinium, l-cyanomethylpyridinium and 1-(2-benzothiazolylmethyhpyridinium. Among the intermediates used in the synthesis of our dyes are trialkoxypropene compounds, aldehydes, esters, ortho esters, and derivatives of dibasic aldehydes such as glutaconicaldehydedianilide hydrochloride.

The preparation of salts having a cation with an active methylene group such as is used in making our dyes is illustrated by the preparations below.

l-PHENACYLPYRIDINIUM BROMIDE Dry pyridine (2 mols., 31.6 g.) and wbromoacetophenone (1 mol., 39.8 g.) where mixed and allowed to stand at room temperature for fifteen minutes. At this point the reaction mixture turned darker in color with the evolution of heat. The reaction mixture was then allowed to stand at room temperature overnight. The product was thrown out of solution by adding an excess of ether with stirring, the ether decanted from the residue, and the product obtained as a solid by refluxing with acetone. The salt was filtered off, washed with acetone and dried. After one recrystallization from ethyl alcohol the yield or pure quaternary salt was 44.5 g. (80%), M.P. 197- 198 C.

4 rl-CYANOMETHYLPYRIDINIUM CHLORIDE Dry pyridine (1 mol., 15.8 g.) and chloroacetonitrile (1 mol., 15 g.) were mixed and allowed to stand at room temperature for fifteen minutes. At this point the reaction mixture evolved heat yielding a light tan solid. The solid cake was then heated on a steam bath for thirty minutes, cooled, ground under acetone, filtered off and dried. After one recrystallization from ethyl alcohol the yield of pure quaternary salt was 25 g. M.P. 178-179 C. dec.

I-(Z-BENZOTHIAZOLYLMETHYL) PYRIDINIUM PERCHLORATE Prepared as described by Walter Ried and Heinz Bender, Chemische Berichte 89, pp. 1893l896 (1956-).

The preparation of our dyes is further illustrated by the following examples.

Example I DYE ll l-phenacylpyridinium bromide (1 mol., 2.78 g.) and p-dimethylaminobenzaldehyde (1 mol.+l00%, 2.98 g.) were dissolved in acetic anhydride (20 ml.) and heated under reflux fifteen minutes. The reaction mixture was then chilled overnight and the crude dye precipitated from the solution as a sticky mass by adding an excess of ether with stirring. The ether solution was decanted, the residue dissolved in water and the dye precipitated as the iodide salt by adding sodium iodide. The crude dye was filtered off, washed with water and dried. After two recrystallizations from aqueous methyl alcohol the yield of pure dye was 2 g. (44%), M.P. 1l9-120 C. dec.

Example II DYE 2 l-phcnacylpyridinium bromide (1 mol., 2.8 g.) and pdimethylaminocinnamaldehyde (1 mol., 1.8 g.) were dissolved in acetic anhydride (30 ml.) and heated under reflux fifteen minutes. The reaction mixture was then chilled overnight and the crude dye precipitated from solution as a sticky mass by adding an excess of ether with stirring. The ether solution was decanted and the residue dissolved in methyl alcohol and the dye precipitated as the perchlorate salt by adding a saturated aqueous sodium perchlorate solution with stirring. The crude dye was filtered off, washed with a small amount of water and dried. After two recrystallizations from methyl alcohol the yield or pure dye was 1.4 g. (31%), M.P. 184-185 C. dec.

Example III DYE 3 9-formyljulolidine (1 mol., g.) was added to a well stirred 0 C. solution of concentrated sulfuric acid (10.5 moles, 500 g). The solution was held at 0 C. and paraldehyde (1 mol., 61 g.) added dropwise with constant stirring. After the addition was complete the solution was stirred for one and one-half hours, poured into ice and treated with sodium carbonate (78 g.). At this point a large amount of black tar-like solid sepa rated which was filtered 01f and suspended in water. The suspension was made alkaline with sodium carbonate and filtered. The solid material was treated with several portions of refluxing ligroin (90-120), these portions were combined, chilled and the precipitate collected on a filter and dried. The solid was then distilled under reduced pressure, B.P. 185-215 at 0.5 mm. After one recrystallization from ethyl alcohol the yield of 9-formylvinyl julolidine was 14.6 g. (13%), M.P. 1l5117 dec.

l-phenacy-lpyridinium bromide (1 mol., 1.39 g.) and 9-formylvinyljulolidine (1 mol., 1.13 g.) were dissolved in acetic anhydride (30 ml.) and heated under reflux fifteen minutes. The reaction mixture was then chilled overnight and the crude dye precipitated from solution by adding an excess of ether with stirring. The dye was filtered off, dissolved in' methyl alcohol and precipitated as the iodide salt by adding an aqueous sodium iodide solution with stirring. The crude dye was then filtered olf, washed with .a small amount of water and dried. After two recrystallizations from water, the yield of pure dye was 1.8 g. (70%), M.P. 221 222 C. dec.

Example IV DYE 4 l-cyanomethylpyridinium chloride (2 mols., 311 g.) and diethox'ymethyla'cetate (1'mol.+-100%, 3.2 g.) were dissolved in dry pyridine (30 ml.) and heated under reflux for fifteen minutes; The reaction mixture was then chilled overnight and the crude dye'filtered 01f, dissolved in water and precipitated as the perchlorate salt by adding sodium perchlorate. The crude dyewas filtered ofl, washedwith a small amount of water and dried. After two recrystallizations from water, the yield of pure dye was 1.4 g. (40%), M.P. 130l'31 C. dec.

Alternatively Dye 4 was produced by the above reaction in which an equimolecular amount of triethylorthoformate was used in place of diethoxymethylacetate.

Example V a V DYE 5 l-phenacylpyridinium bromide (2 mols., 5.56 g.), trimethoxypropene (1'mol.+100%, 2.64 g.) and triethylamine (2 mols., 2.8 ml.) were dissolved indry pyridine (30 ml.) and heated under reflux for twenty minutes. The reaction mixture was then chilled overnight and the crude dye precipitated from solution as a sticky mass by adding an excess of ether with stirring. The ether solution was decanted, the residue dissolved in water and the dye precipitated as the perchlorate salt by adding sodium perchlorate. The crude dye was filtered off, washed with water and dried. After two recrystallizations from methyl alcohol the yield of pure dye was 2.4 g. (45%), M.P. 221-222 C. dec.

Example VI DYE e l-cyanomethylpyridinium chloride (1 mol., 1.55 g.) and p-dimethylaminobenzaldehyde (1 mol.+100%,'3 g.) were dissolved in acetic anhydride (30 ml.) and heated under reflux for fifteen minutes. The reaction mixture was then chilled overnight and the crude dye precipitated from solution as a sticky mass by adding an excess of ether with stirring. The ether solution was decanted, the residue dissolved in water and the dye precipitated as the perchlorate salt by adding sodium perchlorate. The crude dye was filtered off, washed sparingly with water and dried. After two recrystallizations from water the yield of pure dye was 1.2 g. (34%), M.P. 214215 C. dec.

Example VIII DYE 8 This dye was prepared'by'a reaction similar to that of Example VII, but in which cyanomethylpyridinium chloride was reacted with glutaconicaldehydedianilide hydrochloride.

by Table I below.

TABLE I. I

M 1' ht b t' b d" y number: coal- 5 3a ave le glili i ih inu of 1 427 2-; 'L 490 4 475 5 470 Our dyesare readily soluble in water because of th'eir ionic nature and are thus readily incorporated in hydrophilic colloids such as gelatin, polyvinyl alcohols, albumin, casein, etc. which are usually used for such layers. A stock solution may advantageously be made of the dye to be used andthis can simply .be added as desired to'the hydrophilic'colloid before it is tobe coated.

The concentration of the dye used in the hydrophilic colloid may vary considerably depending upon the product in which the filter. layer or the antihalation layer is to be used. The method of determining the proper amount of dye to be used for a given product is well known in the art. I I i In the accompanying drawing, the FIGURES l and 2 are enlarged sectional views of photographic elements having filter layers or antihalation layers made according to our invention. As shown in FIGURE 1,, asupport' 10 of any suitable material such as cellulose acetate, cellulose nitrate, synthetic resin materials or opaque materials such as paper, is coated with an emulsion layer 11 and an overcoating layer 12 containing a cationicdye of our invention.

FIGURE 2 represents a' film having an antihalation layer containing a cationicdye according to our invention. As shown therein, the support 10 carries an emulsion layer 11 and anantihalation layer 13 containing a cationic dye on the opposite side.

The following examples will illustrate more fully how our dyes maybe used in preparing light absorbing filter layers.

Example X 1.5 grams of Dye No. 1 was dissolved in 37 /2 cos. of water and this solution was added to 4.5 liters of 5% aqueous gelatin. This mixture was .then coated as an antihalation backing on .the reverse side of a support which had been coated with a photographic silver halide emulsion layer.

After exposure of the photographic element in the usual manner, development of the exposed material in a developer having the following composition:

1 Grams N-methyl-p-aminophenol sulfate 2 Sodium sulfite (desiccated) Hydroquinone -i. 8 Sodium carbonate monohydrate; 52.2 Potassium bromide 5 Water to make 1 liter.

resulted in complete removal of the dye from the photographic element.

Example XI A photographic element was prepared as in Example X in which Dye-No. '2 was used in place of Dye No. '1. Similarly, development of the exposed image in this photographic element using the developer of Example X resulted in the complete removal of the dye from the photographic element.

2' Example XII A photographic element prepared as in Example X but having Dye N0. 4 in its antihalation backing in place of Dye No. l was freed completely of the dye in the antihalation backing upon development as in Example X.

Example 'XIII Another sample of the photographic element prepared in Example XI I was treated in a conventional sodium thiosulfate fixing bath and the dye in the antihalation Example XIV A photographic element prepared as in Example X but in which Dye No. 6 was substituted for Dye No. 1 gave similar results to those obtained in Example X.

Example XV A mixture of Dye No. l and aqueous gelation solution as prepared in Example X was coated over a light sensitive silver halide emulsion layer on a conventional support.

After exposure of the photographic element in the usual manner, development of the exposed material in the developer of Example X resulted in a complete removal of the dye from the light filtering layer over the developed image.

Example XVI Similarly, the other dyes of our invention can be used in light filtering layers as in Example No. XV.

Although the above examples show the use of our dyes in antihalation layers and in layers overcoating the light sensitive silver halide emulsion layer they may also be coated between light sensitive silver halide layers in multilayer photographic elements.

Some of our dyes are useful as sensitizers for optically sensitizing silver halide (e.g. silver chloride, silver bromide, silver iodide, silver chlorobromide, silver bromoiodide, etc.) emulsion layers in photographic elements. The following table illustrates the wavelengths of light to which the silver halide emulsion layer is sensitized by some of our dyes.

The sensitizing effect is further illustrated by the attached drawings which show wedge spectrograms for two dyes ofour invention.

FIGURE 3 shows the sensitizing effect produced in a silver halide emulsion by our cationic dye 9-(1,2,3,5,6, 7-hexahydrobenzo [i,j] quinolizinyl) allylidenephenacylpyridinium iodide.

FIGURE 4 shows the sensitizing effect produced in a silver halide emulsion by our cationic dye, 1-( a-cyano-pd-imethylaminostyryl)pyridinium perchlorate.

The solubility characteristics of our dyes, as well as the good bleaching characteristics in photographic developers and other processing solutions combined with the sensitizing characteristics shown by some of our dyes makes them useful as sensitizers for photographic elements.

The concentration at which our dyes are used in emulsions as optical sensitizers may vary considerably depending upon the particular photographic product in which they are to be used and the effects desired. The sensitiz ing amounts of a particular dye needed for a particular silver halide emulsion is determined by techniques well known in the art.

The novel cationic oxonol and benzylidene dyes of our invention are characterized by being readily water soluble in neutral solution and more water soluble in slightly acid solution than prior art oxonol dyes, and readily bleachable by ordinary photographic developers and processing solutions. 'These properties make our dyes valuable for use in making light sensitive photographic elements. Some of our dyes are particularly valuable in light absorbing filter layers either overcoating the silver halide emulsion layers or coatings between the light sensitive silver halide layers or coatings on the support of the photographic element over which the light sensitive silver halide emulsion layers are coated. Some of our dyes are also characterized by having useful optical sensitizing effects on photographic silver halide emulsions.

The novel dyes of Formulas I and II of our invention can advantageously be expressed by the formula:

wherein Q represents the non-metallic atoms required to complete a heterocyclic nucleus such as a pyridinium nucleus, a quinolinium nucleus, etc.; Y is a benzoyl group, a cyano group or a benzothiazolyl group; W is an aminoaryl group such as a dimethylaminophenyl group, a diethylaminophenyl group, a dipropylaminophenyl group, a dibutylaminophenyl group, an ethylmethylaminophenyl group, etc., a 1,2,3,5,6,7-hexahydrobenzo[i,j]quinolizinyl group or a group in which Q and Y are as defined above; m is the positive integer l, 2 or 3; and X is an anion.

The invention has been described in detail with particular reference to preferred embodiments thereof but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. A photographic element comprising a support having thereon at least one sensitive silver halide emulsion layer, at least one layer of said photographic element containing a dye selected from those represented by the following two general formulas:

wherein R is a group selected from the class consisting of a hydrogen atom, a bromine atom, a methyl group and a phenyl group, provided when R is selected from the class consisting of a methyl group and a bromine atom, said R group is substituted on the carbon meta to the nitrogen atom of the pyridine ring; Y is a member selected from the group consisting of a cyano group, benzoyl groups, and benzothiazolyl groups; r is -a positive integer of from 1 to 3; n is a positive integer of from 1 to 2; Z is a group selected from the class consisting of aminoaryl groups, and a 1,2,3,5,6,7hexahydrobenzo[i,j] quinolizinyl group; and X is an acid anion.

2. A photographic element comprising a support having thereon at least one sensitive silver halide emulsion layer, at least one layer of said photographic element containing a dye having the formula:

wherein R is a group selected from the class consisting of a hydrogen atom, a bromine atom, a methyl group and a phenyl group, provided when R is selected from the class consisting of a methyl group and a bromine atom, said R group is substituted on the carbon meta to the nitrogen atom of the pyridine ring; Y is a member selected from the group consisting of a cyano group, benzoyl groups; and henzothiazolyl groups; r is a positive integer of from 1 to 3; and X is an acid anion.

B. A photographic element comprising a support having thereon at least one sensitive silver halide emulsion layer, at least one layer of said photographic element containing a dye having the formula:

wherein R is a group selected from the class consisting of a hydrogen atom, a bromine atom, a methyl group and a phenyl group, provided when R is selected from the class consisting of a methyl group and a bromine atom, said R group is substituted on the carbon meta to the nitrogen atom of the pyridine ring; Y is a member selected from the group consisting of a cyano group, benzoyl groups, and benzothiazolyl groups; n is a positive integer of from 1 to 2; Z is a group selected from the class con- 19 sisting of aminoaryl groups and a l,2,3,5,6,7 heXahydrobenzo[i,j]quinolizinyl group; X is an acid onion.

4. A photographic element comprising a support having thereon at least one sensitive silver halide emulsion layer, at least one layer of said photographic element containing the dye l-(a-benzoyl-p-dimethylaminostyryl)- pyridinium iodide.

5. A photographic element comprising a support havin thereon at least one sensitive silver halide emulsion layer, at least one layer of said photographic element containing the dye 1-(p-dimethylaminophenylallylidenephenacyl) pyridinium perchlorate.

6. A photo-graphic element comprising a support having thereon at least one sensitive silver halide emulsion layer, at least one layer of said photographic element containing the dye l-[9-(l,2,3,5,6,7-hexahydrobenzo[i,j] quinolizinyl) a'llylidenephenacyl] -pyridinium iodide.

7. A photographic element comprising a support having thereon at least one sensitive silver halide emulsion layer, at least one layer of said photographic element containing the dye l-(a-cyano-p-dimethylaminostyryl)pyridinium perchlorate.

8. A photographic element comprising a support having thereon at least one sensitive silver halide emulsion layer, at least one layer of said photographic element containing the dye anacid-l,3-dicyanopropenylene bispyridinium perchlorate.

References (Cited in the file of this patent UNITED STATES PATENTS 2,395,879 Kendall et al. Mar. 5, 1946 2,471,996 Anish May 31, 1949 2,656,351 Aubert et a1 Oct. 20, 1953 2,882,160 Stevens Apr. 14, 1959 

1. A PHOTOGRAPHIC ELEMENT COMPRISING A SUPPORT HAVING THEREON AT LEAST ONE SENSITIVE SILVER HALIDE EMULSION LAYER, AT LEAST ONE LAYER OF SAID PHOTOGRAPHIC ELEMENT CONTAINING A DYE SELECTED FROM THOSE REPRESENTED BY THE FOLLOWER TWO GENERAL FORMULAS: 